<template>
    <div>
        <div class="goods">
        <div class="menu-wrapper" ref="menuWrapper">
            <ul>
                <li v-for="(item,$index) in goods" class="menu-item" :class="{'current':currentIndex===$index}" @click="selectMenu($index,$event)">
                    <span class="text" >
                        <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>
                        {{item.name}}
                    </span>
                </li>
            </ul>
        </div>
        <div class="foods-wrapper" ref="foodsWrapper">
            <ul>
                    <li v-for="item in goods" class="food-list food-list-hook">
                        <h1 class="title">{{item.name}}</h1>
                        <ul>
                            <li @click="selectFood(food,$event)" v-for="food in item.foods" class="food-item border-1px">
                                <div class="icon">
                                    <img width="57" height="57" :src="food.icon">
                                </div>
                                <div class="content">
                                    <h2 class="name">{{food.name}}</h2>
                                    <p class="desc">{{food.description}}</p>
                                    <div class="extra">
                                        <span class="count">月售{{food.sellCount}}份</span><span>好评率{{food.rating}}%</span>
                                    </div>
                                    <div class="price">
                                        <span class="now">¥{{food.price}}</span><span class="old" v-show="food.oldPrice">¥{{food.oldPrice}}</span>
                                    </div>
                                    <div class="cartcontrol-wrapper">
                                        <cartcontrol :food="food"></cartcontrol>
                                    </div>
                                </div>
                            </li>
                        </ul>
                    </li> 
            </ul>
        </div>
        <shopcart  :select-foods="selectFoods" :delivery-price="seller.deliveryPrice" :min-price="seller.minPrice"></shopcart>
        </div>
        <food :food="selectedFood" ref="food"></food>
    </div>
</template>

 <script type="text/ecmascript-6">
    import BScroll from 'better-scroll';
    import shopcart from '../shopcart/shopcart.vue';
    import cartcontrol from '../cartcontrol/cartcontrol.vue';
    import food from '../food/food.vue';

    const ERR_OK = 0;

    export default {
        props: {
            seller: {
                type: Object
            }
        },
        data(){
            return {
                goods: [],
                listHeight: [],
                scrollY: 0,
                selectedFood: {}
            };
        },
        computed: {
            currentIndex() {
                for (let i=0;i<this.listHeight.length;i++) {
                    let height1 = this.listHeight[i];
                    let height2 = this.listHeight[i+1];
                    if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)){
                        return i;
                    }
                }
                return 0;
            },
            selectFoods() {
                let foods = [];
                this.goods.forEach((good) => {
                    good.foods.forEach((food) => {
                        if (food.count) {
                            foods.push(food);
                        }
                    });
                });
                return foods;
            }
        },//映射左侧栏
        created() {
            this.classMap = ['decrease','discount','special','invoice','guarantee'],
            this.$http.get('/api/goods').then((response) => {
                response = response.body;
                if (response.errno === ERR_OK){
                    this.goods = response.data;
                    
                    this.$nextTick(() => { 
                        this._initScroll();
                        this._calculateHeight();
                    }); // 在这个函数中调用以防内容还未加载完就执行，获取不到元素的高度导致无法滑动
                }
            });
        },
        methods: {
            selectMenu(index,event){
                if(!event._constructed){
                    return;
                }
                let foodList = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook');
                let ref = foodList[index];
                this.foodsScroll.scrollToElement(ref,300);
            },
            selectFood(food,event) {
                 if(!event._constructed){
                    return;
                }
                this.selectedFood = food;
                this.$refs.food.show();
            },
            _initScroll() {
                this.meunScroll = new BScroll(this.$refs.menuWrapper, {
                    click: true
                });
                this.foodsScroll = new BScroll(this.$refs.foodsWrapper, {
                    click: true,
                    probeType: 3
                });
                this.foodsScroll.on('scroll',(pos) => {
                    this.scrollY = Math.abs(Math.round(pos.y));//pos获取位置，abs取绝对值。
                })
            },
            _calculateHeight() {
                let foodList = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook');
                let height = 0;
                this.listHeight.push(height);
                for(let i=0;i< foodList.length;i++){
                    let item = foodList[i];
                    height += item.clientHeight;
                    this.listHeight.push(height);
                }
            }
        },
        components: {
            shopcart,
            cartcontrol,
            food
        }
    };
</script>

<style lang="stylus" rel="stylesheet/stylus">
     @import "../../common/stylus/mixin.styl"
     
    .goods
        display: flex
        position: absolute
        top: 174px
        bottom: 46px
        width: 100%
        overflow: hidden
        .menu-wrapper
            flex: 0 0 80px
            width: 80px
            background: #f3f5f7
            .menu-item
                display: table
                height: 54px
                width: 56px
                padding: 0 12px
                line-height: 14px
                &.current
                    position: relative
                    z-index: 10
                    margin-top: -1px
                    background: #fff
                    font-weight: 700
                    .text
                        border-none()
                .icon
                    display: inline-block
                    vertical-align: top
                    width: 12px
                    height: 12px
                    margin-right: 2px
                    background-size: 12px 12px
                    background-repeat: no-repeat
                    &.decrease
                        bg-image('decrease_3')
                    &.discount
                        bg-image('discount_3')
                    &.guarantee
                        bg-image('guarantee_3')
                    &.invoice
                        bg-image('invoice_3')
                    &.special
                        bg-image('special_3')
                .text
                    display: table-cell
                    width: 56px
                    vertical-align: middle
                    border-1px(rgba(7,17,27,0.1))
                    font-size: 12px
        .foods-wrapper
            flex: 1
            .title
                padding-left: 14px
                height: 26px
                line-height: 26px
                border-left: 2px solid #d9dde1
                font-size: 12px
                color: rgb(147,153,159)
                background: #f3f5f7
            .food-item
                display:flex
                margin: 18px
                padding-bottom: 18px
                border-1px(rgba(7,17,27,0.1))
                &:last-child
                    border-none()
                    margin-bottom: 0
                .icon
                    flex: 0 0 57px
                    margin-right: 10px
                .content
                    flex: 1
                    .name
                        margin:2px 0 8px 0
                        height: 14px
                        line-height: 14px
                        font-size: 14px
                        color: rgb(7,17,27)
                    .desc,.extra
                        line-height: 10px
                        font-size: 10px
                        color: rgb(147,153,159)
                    .desc
                         line-height: 12px
                         margin-bottom: 8px
                    .extra
                        .count
                         margin-right:12px
                    .price
                         font-weight: 700
                         line-height: 24px
                        .now
                            margin-right: 8px
                            font-size: 14px
                            color: rgb(240,20,20)
                        .old
                            text-decoration:line-through
                            font-size: 10px
                            color: rgb(147,153,159)
                    .cartcontrol-wrapper
                        position: absolute
                        right: 0
                        bottom: 12px

</style>    